<s>
KarTrak	B-Application
,	O
sometimes	O
KarTrak	B-Application
ACI	I-Application
(	O
Automatic	O
Car	O
Identification	O
)	O
is	O
a	O
colored	O
barcode	O
system	O
designed	O
to	O
automatically	O
identify	O
railcars	O
and	O
other	O
rolling	O
stock	O
.	O
</s>
<s>
KarTrak	B-Application
was	O
made	O
a	O
requirement	O
in	O
North	O
America	O
,	O
but	O
technical	O
problems	O
led	O
to	O
the	O
abandonment	O
of	O
the	O
system	O
in	O
the	O
late	O
1970s	O
.	O
</s>
<s>
General	O
Electric	O
developed	O
an	O
RFID	B-Application
system	O
,	O
ABEX	O
a	O
microwave	O
system	O
,	O
Wabco	O
a	O
black-and-white	O
barcode	O
system	O
,	O
and	O
General	O
Telephone	O
&	O
Electronics	O
(	O
GTE	O
)	O
a	O
color	O
barcode	O
system	O
called	O
KarTrak	B-Application
.	O
</s>
<s>
All	O
those	O
systems	O
,	O
except	O
the	O
RFID	B-Application
system	O
,	O
had	O
labels	O
that	O
were	O
mounted	O
on	O
each	O
side	O
of	O
the	O
railcar	O
,	O
and	O
a	O
trackside	O
scanner	O
.	O
</s>
<s>
After	O
the	O
initial	O
field	O
tests	O
,	O
the	O
ABEX	O
,	O
Wabco	O
,	O
and	O
GTE	O
KarTrak	B-Application
ACI	I-Application
systems	O
were	O
selected	O
for	O
a	O
head-to-head	O
accuracy	O
test	O
on	O
the	O
Pennsylvania	O
Railroad	O
,	O
at	O
Spruce	O
Creek	O
,	O
Pennsylvania	O
.	O
</s>
<s>
The	O
KarTrak	B-Application
system	O
was	O
declared	O
the	O
winner	O
and	O
selected	O
by	O
the	O
AAR	O
as	O
the	O
standard	O
.	O
</s>
<s>
Without	O
maintenance	O
,	O
the	O
read	O
rate	O
failed	O
to	O
improve	O
,	O
and	O
the	O
KarTrak	B-Application
system	O
was	O
abandoned	O
by	O
1977	O
.	O
</s>
<s>
KarTrak	B-Application
ACI	I-Application
tags	O
consisted	O
of	O
a	O
plate	O
with	O
13	O
horizontal	O
labels	O
put	O
in	O
a	O
vertical	O
arrangement	O
that	O
are	O
also	O
understood	O
as	O
data	O
lines	O
,	O
which	O
could	O
have	O
13	O
different	O
forms	O
.	O
</s>
<s>
Line	O
13	O
:	O
check	B-Error_Name
digit	I-Error_Name
.	O
</s>
<s>
The	O
check	B-Error_Name
digit	I-Error_Name
is	O
calculated	O
as	O
follows	O
:	O
Each	O
number	O
digit	O
is	O
multiplied	O
by	O
two	O
to	O
the	O
power	O
of	O
the	O
labels	O
's	O
position	O
minus	O
two	O
.	O
</s>
<s>
The	O
sum	O
of	O
all	O
these	O
numbers	O
modulo	O
is	O
the	O
check	B-Error_Name
digit	I-Error_Name
.	O
</s>
<s>
This	O
means	O
a	O
car	O
with	O
equipment	O
code	O
number	O
8	O
,	O
ownership	O
code	O
350	O
,	O
which	O
lists	O
this	O
as	O
a	O
car	O
of	O
the	O
Illinois	O
Central	O
Railroad	O
,	O
car	O
number	O
199918	O
,	O
with	O
a	O
check	B-Error_Name
digit	I-Error_Name
of	O
5	O
.	O
</s>
<s>
The	O
first	O
systems	O
were	O
discrete	O
circuits	O
and	O
logic	O
and	O
only	O
provided	O
an	O
ASCII-coded	O
list	O
of	O
the	O
labels	O
that	O
passed	O
the	O
scanner	O
.	O
</s>
<s>
Later	O
reading	O
systems	O
were	O
coupled	O
with	O
era	O
minicomputers	B-Architecture
(	O
Digital	B-Device
Equipment	I-Device
Corporation	I-Device
PDP-8s	I-Device
)	O
,	O
and	O
more	O
elaborate	O
tracking	O
and	O
weighing	O
systems	O
were	O
integrated	O
.	O
</s>
<s>
The	O
KarTrak	B-Application
system	O
proved	O
to	O
need	O
too	O
much	O
maintenance	O
to	O
be	O
practical	O
.	O
</s>
<s>
Its	O
place	O
was	O
eventually	O
taken	O
by	O
the	O
RFID-based	O
approach	O
.	O
</s>
<s>
Between	O
1967	O
and	O
1977	O
,	O
the	O
railroad	O
industry	O
spent	O
$150	O
million	O
on	O
KarTrak	B-Application
,	O
and	O
up	O
to	O
95%	O
of	O
cars	O
were	O
barcoded	O
.	O
</s>
<s>
Older	O
cars	O
can	O
often	O
still	O
be	O
seen	O
with	O
a	O
KarTrak	B-Application
label	O
.	O
</s>
<s>
KarTrak	B-Application
label	O
decals	B-Application
are	O
readily	O
available	O
for	O
different	O
model	O
railroad	O
scales	O
.	O
</s>
